A source close to the singer's ex-husband, Kevin Federline, claims to ET that Britney's father, Jamie, "engaged in conduct that was physical abuse" toward their 13-year-old son, Sean.
According to the source, the alleged incident of abuse resulted in Kevin and his divorce attorney, Mark Vincent Kaplan, to file a police report with law enforcement in Ventura County, California.
In addition to Sean, Britney and Kevin also share 12-year-old son Jayden. At this time, a source close to Kevin claims he has physical custody of both his and Britney's children. The source claims Britney has 10 percent custodial rights while Kevin gets the boys 90 percent of the time.
A source also claims that the alleged physical abuse took place while the children and Britney were visiting Jamie's home in Westlake Village, California. ET has reached out to Britney and Jamie's attorneys for comment, as well as authorities.
Late last month, Britney took to Instagram to share her feelings about not knowing who to trust. "Living in LA is such a trip !!! It can be lonely at times. You never know who to trust, and some people can be fake," she captioned the post. "I have a very small circle of friends, and simply do what makes me happy!!! It breaks my heart to see the comments on my posts sometimes .... So I simply choose not to look anymore ... let the clever haters do what they do best .... hate!!!"
It hasn't been an easy year for Britney, who has faced plenty of ups and downs over the past few months. Back in April, the pop star checked herself into a health facility. A source told ET at the time that she made the decision in order to deal with the tremendous stress she had been having over her father's current health crisis.
Shortly after, however, her fans sparked the #FreeBritney campaign after they claimed that the singer -- who is under a conservatorship -- was being held against her will at the facility. ET then learned that despite the protests by some of her fans, the singer has the freedom to go where she wants, but must have a security escort and isn't allowed to go to places like liquor stores.
Last month, ET obtained court documents filed in connection to Britney's conservator case, which revealed that her father took home $128,000 of the over $1.1 million in expenses from her legal and conservator fees. Jamie has served as her conservator since 2008, and became her sole conservator after his former co-conservator, Andrew Wallet, resigned earlier this year.
Hear more on Britney and her family in the video below.